[PATCH net-next]: net: remove ifalias on empty given alias

This patch removes the potentially allocated ifalias when the (new) given alias is empty.

E.g. when setting

echo "" > /sys/class/net/eth0/ifalias

Signed-off-by: Oliver Hartkopp <redacted>
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Hello Stephen,

this patch allows to 'remove' or reset the ifalias by giving an empty alias.
The patch is tested.
Btw. ifalias is a nice idea also for CAN bus people to 'name' a given CAN bus.

Thanks & regards,
Oliver